WALTHAM, Mass. — After a promising start to his second NBA season, everything changed for MarShon Brooks when he stepped on Andray Blatche’s foot during a shootaround in Orlando before the Nets’ fourth game of the season.

Brooks averaged 10.3 points in about 20 minutes through three games, but after sitting out three contests with an ankle injury, he never found a consistent place in the team’s rotation.

“It was tough,” Brooks said yesterday after being introduced, along with Keith Bogans and Kris Humphries, as the newest members of the Celtics as the counterbalance to Paul Pierce, Kevin Garnett and Jason Terry going to Brooklyn. “The reason why it was tough was because I never really felt that I got beat out of my situation. I never really feel like I got beat.

“I feel like it was given … my minutes were given away. I was playing the first three games of the year, I was playing 25 minutes and shooting 60-something percent from the field at the time, went down with a freak injury in shootaround, and when I came back, nothing was the same.

“So I felt like honestly I was on my way to a really good year if things had stayed that way … but I learned a lot, man. I learned a lot.”Things turned out differently, as Brooks spent much of the year sitting behind more experienced players with the playoff-bound Nets. Now, though, he’s excited for the possibilities in Boston, and the potential of playing alongside All-Star point guard Rajon Rondo.

Despite the presence of six-time All-Star Joe Johnson at his position entering training camp last year, Brooks entered the season confident he could still have an impact, and stated he hoped to claim the league’s Sixth Man award.

“I’m so excited man, but I understand that nothing’s going to be given,” he said. “They’ve got a couple of young guards, and the main thing for me is just working hard. It starts now, and whenever they roll those balls out I will be 110 percent ready to play.”

Not only has the blockbuster trade with the Celtics had an impact on the Nets’ expectations for next season, but it also has had an impact on the team’s take at the box office.

* The Nets said they have sold more than $3 million in season tickets since June 27, the night of the NBA Draft when the trade with the Celtics was agreed upon.

A league source said the Nets were fewer than 1,000 tickets short of their 13,000 cap on season tickets for the 2013-14 season. Group and individual tickets will go on sale in September.

The acquisitions of Pierce, Garnett, Terry and Andrei Kirilenko — the team’s first Russian player since Mikhail Prokhorov bought the team — have led the team to begin a new marketing campaign, “Hello Brooklyn. We’re In.” It will feature all four players, and plays off last summer’s “Hello Brooklyn” campaign to introduce the team to the borough.